This section is intended to provide a background to the various embodiments of the technology described in this disclosure. The description in this section may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and/or claims of this disclosure and is not admitted to be prior art by the mere inclusion in this section.
To improve the throughput of wireless communication systems so as to provide high-speed data services to a large amount of terminal devices, it has been proposed to employ a frequency spectrum which is much higher than those where conventional systems (such as the 2nd-4th (2G-4G) systems) are deployed. At such a spectrum (in the order of tens of GHz, for example), the atmospheric attenuation, penetration and diffraction properties of electromagnetic waves are much worse than at relatively lower frequencies. In addition, the link budget would be worse for the same link distance even in a free space scenario. This motivates the use of beamforming to concentrate the energy of transmitted wireless signals to compensate for the loss of link budget in high-frequency spectrum.